This question is about ACTG 384, an HIV clinical trial comparing four 3-drug HIV treatment regimens. One of the outcomes

[answerhappygod]

This question is about ACTG 384, an HIV clinical trial comparing
four 3-drug HIV treatment regimens. One of the outcomes was regimen
failure; for simplicity we just categorize this as "yes" versus
"no", ignoring the fact that some patients left the study earlier
than originally planned (so-called loss to follow-up). The relevant
data:
Treatment Number
of patients Number
of patients Number of patients
with
regimen failure without regimen
failure
1
155
76
79
2
155
66
89
3
155
56
99
4
155
74
81
a. We are going to carry out a test for dependence of treatment
regimen and regimen failure. Provide the null and alternative
hypotheses.*
b. We are going to carry out a test for dependence of treatment
regimen and regimen failure. Provide the expected number of
patients with regimen failure and also the expected number of
patients without regimen failure for each of the regimens if
treatment and regimen failure are independent.
c. Calculate Pearson's chi-squared statistic for the test of
independence between treatment regimen and regimen failure.